Carbon Brush will consumed and needed to be replaced after certain flying time,

Silver brush gives you more torque than Carbon Brush (ESL-003) but its life is 30% Shorter.

by Michael Aires

These little guys offer much more power than the carbon brushes in my opinion. If you like to fly fast and do a few lama tricks as I call them, then you may want to consider these especially if you have the SE 180 motors. The only downside is that they do wear faster than the carbon, but not a big deal for me. More power = more fun!!!
Regards,
Michael